Field of the Invention
The present invention relates to a dielectric ceramic composition for sintering at a low temperature and more particularly, to a composition of the formula (Pb(Zr.sub.1/2 Ti.sub.1/2)O.sub.3)x, (Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3)Y and (Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3)z, wherein x plus y plus z equal 1, which is sintered at a low temperature so as to be suitable as a material for laminated ceramic capacitors and has a high dielectric constant.
2. Description of the Prior Art
Various high dielectric constant ceramic compositions are well known in the art. Also, various high dielectric constant ceramic compositions have BaTiO.sub.3, BaSnO.sub.3, CaTiO.sub.3, or PbTiO.sub.3 as their principal components, with sintering temperature above 1,100.degree. C. and dielectric constant of 2,000 at room temperature. Therefore, in the event of applying such compositions to a laminated capacitor, inclusion of a precious metal such as Ag-Pd, Au, Pt, or Pd in the compositions produces high corrosion resistance at the sintering temperature of above 1,100.degree. C. for use as electrodes. Such dielectric ceramic compositions are disclosed in Japanese Patent No. 56-46641 which discloses a dielectric ceramic composition of a formula ((Ba.sub.1 -xCax)O)m and (Ti.sub.1 -yZry)O.sub.2, wherein 1.005.ltoreq.x.ltoreq.1.03, 0.02.ltoreq.x.ltoreq.0.22, and 0.ltoreq.y.ltoreq.0.20). However, the necessity of using a precious metal for electrodes introduces an element of economic disadvantage. To avoid such disadvantages, Korea Patent Laid-Open Nos. 87-5418 and 87-6597 and Korean Patent Publication No. 86-1758 disclose a small amount of addition impurities to the basic composition. However, the sintering temperature thereof still remains high such as above 1,000.degree. C.